Measurement of electron temperature and number density in shock-tunnel flows. II

Dunn, Michael G.; Lordi, J. A.

doi:10.2514/3.5563

Cited by 27 publications

(7 citation statements)

References 13 publications

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“…24), langmuir probes, or microwave devices, 25 " 27 have not yet been fully explained either by the experimental work of Sharma et al, 20 -21 the theoretical work of Ruff in, 13 or the present work. In general, those experimental data show vibrational temperatures lower than predicted by the latest theories.…”

Section: Discussionmentioning

confidence: 74%

“…Apparently, at the high vibrational temperature, suspension of Eq. (25) does not lead to a large error. Here, the choice of m = 4 and n = 6 is seen to give the closest agreement with Ruffin's calculation below 60,000 cm" 1 .…”

Section: Ruffin's Theoretical Calculationmentioning

confidence: 90%

“…(19) can be set to zero, leading to This means that the value of p is unity at the dissociation limit P(r m ) = 1 (25) the slope is zero at the dissociation limit -« (26) and the curvature at the dissociation limit iŝ kT…”

Section: Behavior At Dissociation Limitmentioning

confidence: 99%

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Estimation of excitation energy of diatomic molecules in expanding nonequilibrium flows

Park

1995

Journal of Thermophysics and Heat Transfer

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The energy contained in the highly excited vibrational and rotational states in a diatomic gas in a thermochemical nonequilibrium state during expansion is estimated. The population distribution of the vibrational and rotational states is assumed to be describable by a polynomial. The parameters in the polynomial are determined by invoking known physical constraints. The energy contained in the internal states in excess of that accounted for in the conventional method is calculated for N 2 , O 2 , NO, CO, and H 2 . The calculation is carried over a wide range of conditions, and the results are fitted with polynomials. The population distributions so determined agree with the theoretical and experimental results of others. A sample calculation made for a typical nozzle flow shows that the excess energy may reach 6% of the total enthalpy of the flow, and that the flow velocity may decrease by 3% due to this phenomenon. NomenclatureA = cross-sectional area of nozzle a { = coefficients of expansion of p, Eq. (29) c -continuum state D = dissociation energy measured from the ground vibrational state, eV or cm" 1 E = combined vibrational-rotational energy (E v + £,.), eVor cm" 1 E(i) = energy level of state /, eV or cm" 1 E r = rotational energy per molecule, eV or cm" 1 E v = vibrational energy per molecule measured from the ground vibrational state, eV or cm" 1 £ v = excess vibrational-rotational energy per unit mass, J/kg, Eq. (3) g = rotational statistical weight, 2J + 1 H = enthalpy /, /' = indices representing an internal state J = rotational quantum number K(i, /') = rate coefficient for collisional transition from state / to state /', m 3 /s k = Boltzmann constant M = see Eq. (8) m = exponent in Eq. (29) n = exponent in Eq. (29), or number density, m~3 n E (i) = number density of state / in equilibrium, m~3 n(i) = number density of state /, m~3 n x = number density of colliding particles, m" 3 p = pressure, atm Q = partition function R = absolute radius in E v vs E r coordinate system, eV or cm" 1 , Eq. (10) r = normalized radius, Eq. (11) T = heavy particle translational temperature, K T r = rotational temperature defined by lowest two states, K T v = vibrational temperature defined by lowest two states, K / = time, s V -flow velocity, m/s v -vibrational quantum number v -average thermal speed, m/s a = kTID dT r = see Eq. (16) 8T V = see Eq. (13) E = vibrational-rotational energy, eV or cm" 1 6 = characteristic vibrational temperature (co e /k), K 0 -polar angle in E v vs E r coordinate system, rad, Eq. (12) p(i) = normalized nonequilibrium population for state «, Eq. (5) p M = normalized nonequilibrium molecular density, Eq. (38) p = fluid density, kg/m 3 cr = excitation cross section, m 2 o} e = first vibrational constant, eV co e x e = second vibrational constant, eV Subscripts A = atomic species A av = average energy B -atomic species B E = equilibrium M = molecule m = maximum value s = settling chamber 0 = origin in E v vs E r coordinate system Superscript

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Section: Discussionmentioning

confidence: 74%

Section: Ruffin's Theoretical Calculationmentioning

confidence: 90%

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Estimation of excitation energy of diatomic molecules in expanding nonequilibrium flows

Park

1995

Journal of Thermophysics and Heat Transfer

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“…In the test campaign described in Dunn and Lordi (1969), electron temperatures and electron densities have been measured in the Calspan nozzle; the working gas was air and the equilibrium reservoir conditions were T 0 =6850 K and P 0 =0.94738 MPa. Geometry and grid used in this test is reported in Battista (2009).…”

Section: Validation Test 2 -Ionization Chemistry In An Expansion Expementioning

confidence: 99%

“…The second reaction rate coefficient has been taken from (Gokcet 2004). For air ionization one of the most important reactions governing the distribution of free electrons present in high temperature air plasmas is (Dunn & Lordi 1969):…”

Section: Chemical Modelmentioning

confidence: 99%

A Magneto-Fluid-Dynamic Model and Computational Solving Methodologies for Aerospace Applications

Battista¹,

Misuri²,

Andrenucci³

2012

Fluid Dynamics, Computational Modeling and Applications

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A shock tube method in the kinetic study of nonequilibrium ionization-recombination by rarefaction wave cooling

et al. 2005

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Measurement of electron temperature and number density in shock-tunnel flows. II

Cited by 27 publications

References 13 publications

Estimation of excitation energy of diatomic molecules in expanding nonequilibrium flows

Estimation of excitation energy of diatomic molecules in expanding nonequilibrium flows

A Magneto-Fluid-Dynamic Model and Computational Solving Methodologies for Aerospace Applications

A shock tube method in the kinetic study of nonequilibrium ionization-recombination by rarefaction wave cooling

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